Season 10 of American Idol premieres tonight, but new host Steven Tyler has already made some great talk show appearances on the Late Show With David Letterman, Late Night With Jimmy Fallon (watch his performance below), The Howard Stern Show and Live With Regis and Kelly. On Fallon last night, Tyler marveled at sitting in the same chair as Keith Richards and broke into "Walk This Way" with the Roots and Fallon acting as hype man.

But Tyler's longest, most in-depth interview came yesterday in a surprise visit to The Howard Stern Show, where he discussed the events that led him to accept the job as a judge on Idol – a decision bandmate Joe Perry called "one step above Ninja Turtles" – along with details on rehab, his audition with Led Zeppelin and Aerosmith’s new album. The band is re-forming in L.A. this Saturday (without Perry) to begin working on its first album of original material since 2001's Just Push Play.

Tyler said trouble first began within the band when he took a year off to battle hepatitis C, which he announced in 2006. "It was beyond hell," he said. "Three months in, my wife left me for being unfaithful on the road. All these things, it just crippled me, wore me down." After 12 years of sobriety, Tyler began using drugs again, which led him to fall off a stage in 2009 in South Dakota. "I was using and fell off the stage," he said. "I was snorting fuckin' Lunesta. I got 19 stitches, broke my shoulder. No one in the band called me for 27 weeks. It about killed me. I'm Italian so it almost took me down....Joe didn't come visit me."

Tyler and Perry last spoke "a long time ago, on tour," Tyler said, saying he only communicates with Perry through text messages or going through Joe's wife, Billie. "I think he's bummed out I'm sober," said Tyler. Later he said, "Maybe I'm not the only guy in the band using."

(Two weeks ago, Tyler told Rolling Stone that he was ready to record a new Aerosmith album, but he couldn't find Perry.)

This Saturday, the band is going to rehearse in L.A. "We're gonna get in a room together and write some shit. Tom, Joey, Brad will be there. Joe is Missing in Action. I texted him 20 minutes ago. 'Hey, Joe: Where are you?' He's angry with me for what? Because I took fuckin' Idol? What a crock of shit." He added Tom Hamilton will sing a song on the upcoming record.

Tyler also discussed his jam session with the members of Led Zeppelin after Robert Plant opted not to tour with them after their 2007 reunion gig. "When I looked Jimmy [Page] in the eyes and he said 'Wanna write a record with me?' I said, 'No,'" Tyler said. "I have such an allegiance to my band and I love it so much." He said he and Page might do some select "one-off" gigs in the future. Despite the cold relationships in the band, Tyler revealed the band already has dates booked in South America and Japan later this year.

As an Idol judge, Tyler admitted he's not another Simon Cowell, and, against Stern's wishes, you won't regularly find him critiquing contestants' physical appearances. "You can't prejudice a situation like that," he told Stern. "To a certain extent, you can say, 'You don't look like a star, you don't walk, talk and act like a star so get out of there.'"

"I'm looking for the next Joplin, the one that isn't vocorded," he said. "The times that I found one, I teared up out there."